I definitely understand your frustration, forgive me for LOL about throwing him out on the freeway.
You gave him some great advise and hopefully it will be beneficial to him. His location makes it a bit more difficult, but I am sure there is a way for him to attain assistance in training. Having two young ones like that is going to be a real hand full by the time they reach their 'teenage' period. Then he will also have to deal with size and antics.
I hope he will feel comfortable enough to contact you with any questions or advise he may need in the future and will find that keeping them indoors and crate trained would be a great advantage for him. They are not hard to housebreak.
Like you said they are very intelligent, he just has to be smarter than they are or they will take over. Alpha position is very important with any canine, discipline, guidelines and structure is what they expect and need to become the best they can. That applies to all be it small or large. But with the large and giants it is a must to start very early because of their adventual size and power. An out of controlled large or giant is an 'accident' waiting to happen.
I think you handled it very well.......though I am still LOL about the 'throwing him out on the freeway'
Keep us informed on how the saga progresses.